Caliper for a disk brake for a high-performance motorcar

ABSTRACT

A caliper for disk brakes for high-performance cars, which has a high degree of reliability, comprises a body having two side portions and two transverse bridges connecting the two side portions, cylinder-piston units arranged along each side portion, and a circuit for a fluid for cooling the cylinder-piston units, the circuit comprising wells which are formed along the side portions and are of a depth such that they extend substantially as far as the wall delimiting the cylinder-piston units, and which are closed by covers, the circuit also comprising connecting ducts between adjacent wells.

BACKGROUND OF THE INVENTION

The present invention relates to a caliper for disk brakes formotorcars, particularly high-performance cars, of the type comprising abody having two side portions and two transverse bridges connecting thetwo side portions, cylinder-piston units arranged along each sideportion, and a circuit with an inlet and an outlet for a fluid forcooling the cylinder-piston units.

As is known, in calipers of the type specified, it is necessary to coolthe cylinder-piston units so that the braking fluid does not reachexcessively high temperatures which would lead to boiling of the brakingfluid and consequently to loss of braking efficiency.

In known calipers, although the circuits for the cooling fluid used upto now for preventing the braking fluid from reaching excessively hightemperatures are substantially satisfactory, they have recognizeddisadvantages.

For example, there are known calipers which have cooling-fluid circuitsconstituted by ducts formed in the caliper body during casting. Theseducts extend along the side portions of the caliper and their pathextends past the walls of the cylinder-piston units. However, this knownsolution requires the caliper bodies to be produced by casting with thedisadvantage of structural complexity of the body.

Calipers which have fluid ducts, particularly air ducts, which extendalong the cylinder-piston units in the vicinity of the region of contactwith the braking pads have also been proposed. However, this lattersolution is penalized by the poor heat-removal capacity typical of air,and requires very large ducts.

The technical solution of fitting, on the caliper body, elements havingducts through which a cooling liquid, rather than air, is intended toflow, however, have the disadvantage of requiring dimensions which arenotably large, although smaller than those of solutions in which thecooling fluid is air.

SUMMARY OF THE INVENTION

The problem upon which the present invention is based is therefore todevise a caliper of the type specified which has structural andfunctional characteristics such as to satisfy the above-mentioned needto cool the cylinder-piston units, at the same time overcoming thedisadvantages mentioned with reference to the prior art.

This problem is solved by a caliper of the type specified which ischaracterized in that the circuit for the fluid for cooling thecylinder-piston units comprises wells formed along at least one of theside portions, the wells being of a depth such that they extendsubstantially as far as the vicinity of the wall delimiting at least oneof the cylinder piston units, and the wells being closed by covers, thecircuit also comprising connecting ducts for putting the wells intofluid communication with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and the advantages of the caliper according tothe present invention will become clear from the following descriptionof embodiments thereof given by way of non-limiting example andillustrated in the appended drawings, in which:

FIG. 1 is a view showing a first embodiment of the caliper according tothe invention, in longitudinal section,

FIG. 2 is a perspective view of the caliper of FIG. 1 with partsseparated, viewed substantially from below and from the rear,

FIG. 3 is a perspective view of the caliper of FIG. 1 with partsseparated, taken from above and from the rear,

FIG. 4 is a perspective view of the caliper of FIG. 1, with partsseparated, taken from above and from the front,

FIG. 5 is a shows a variant of the caliper of the preceding drawings, inlongitudinal section,

FIG. 6 is a perspective view of the caliper of FIG. 5, taken from below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the appended drawings, a caliper for a disk brakeintended for a motorcar in general and for a high-performance motorcarin particular, is generally indicated 1.

The caliper 1 comprises a body 2 produced by machining from a solidsemi-finished product, for example, from a rolled piece or from aforging of a suitable aluminium alloy known per se.

The body 2 has opposed elongate side portions 3 and 4 which are intendedto be arranged along opposed sides of a braking band of the disk of adisk brake, not shown in the drawings.

The side portion 3 is disposed on the inner side and the side portion 4is disposed on the outer side of the disk, in conventional manner.

Each of the side portions 3 and 4 has a lower peripheral wall 3 a, 4 aand an upper peripheral wall 3 b, 4 b.

Two transverse connecting bridges 5 and 6 connect the two side portions3 and 4 to one another at their respective ends and on the side with theperipheral walls 3 b and 4 b. These connecting bridges 5 and 6 extendover the braking band of the disk.

The caliper 1 is of the fixed type and is intended to be fixed to anaxle of the motor vehicle in conventional manner.

Cylinder-piston units are arranged along each of the two side portions 3and 4. In the embodiment illustrated, four cylinder-piston units 7, 8, 9and 10 are disposed in the side portion 3 and four cylinder-piston units11, 12, 13 and 14 are disposed in the side portion 4.

The respective cylindrical seat of the cylinder of each cylinder-pistonunit 7-14 in which the respective piston, not shown, can slide, isindicated 7 a-14 a.

A fluid circuit 15 for a braking fluid supplies all of thecylinder-piston units in conventional manner known per se.

According to the present invention, the caliper 1 comprises a fluidcircuit 16 for a cooling fluid, for example water, which is provided forcooling the cylinder-piston units 7-14 and, more precisely, for coolingthe braking fluid operating therein, in order to avoid the danger ofboiling of the braking fluid.

The fluid circuit 16 for the cooling fluid has a path 17 which extendsbetween two connectors 18 and 19 which constitute the inlet and theoutlet for the cooling fluid.

Wells are formed in the lower walls 3 a and 4 a of the side portions 3and 4, preferably by mechanical milling with machine tools. Moreprecisely, according to the embodiment shown in FIGS. 1-4, three wells20, 21, 22 and 23, 24, 25, respectively, are formed in each side portion3 and 4, each in a position between respective adjacent cylinder-pistonunits.

Each well 20-25 has a substantially cusp-shaped end 20 a-25 a fittedbetween the respective adjacent cylinder-piston units so that the ends20 a-25 a of the wells are close to the walls delimiting the cylindricalseats 7 a-14 a and hence are in a good heat-exchange relationshiptherewith.

The wells 20-25 are closed in a leaktight manner by respective covers 20b-25 b, for example, by means of conventional screws, or by snap-closuremeans, or even by gluing, leaktightness being ensured by respectiveseals 20 c-25 c.

The well 21 and the well 24, which are deeper, are closed by the covers21 b and 24 b. These have appendages 26 and 27 which project into therespective wells 21 and 24 defining respective spaces 28 of limitedtransverse dimensions.

The wells 20 and 21, as well as the wells 23 and 24 are in fluidcommunication with one another by means of respective ducts 29. Thewells 21 and 22 as well as the wells 24 and 25 are in fluidcommunication by means of ducts 30.

The ducts 29 and 30 are produced by drilling along two intersectingaxes.

The well 22 is put into fluid communication with the well 25 by means ofa conventional duct, not shown, and the well 23 is put intocommunication, by means of a further duct, not shown, with a threadedhole 31, opening into the inner side of the side portion 3. Theconnector 19 is screwed into the threaded hole 31 on the outside of thecaliper. A threaded hole 32 is formed in the cover 20 b. This hole 32which, in practice, is on the outside of the caliper in the same manneras the threaded hole 31, houses the connector 18 which is screwedtherein.

It is clear at this point that the circuit 16 for the cooling liquid isconstituted by the spaces 28 formed by the covers 20 b-25 b with theends of the respective wells 20-25, by the ducts 29 and 30, and by thetransverse connecting ducts (not shown) which put the well 22 intocommunication with the well 25 and the well 23 into communication withthe threaded hole 31.

All of the covers 20 b-25 b are made of aluminium. The appendages 26 and27 formed integrally with the respective covers 21 b and 24 b are alsomade of aluminium.

In operation, the cooling fluid which passes along the path 17 of thecircuit 16 flows through the ducts, close to the cylinder-piston units,ensuring that the temperature of the braking fluid is kept below itsboiling points.

With reference to the embodiment of FIGS. 5 and 6, it will be noted thatthe circuit for the fluid for cooling the cylinder-piston unitscomprises, for each side portion 3 and 4, two wells, indicated 33 and34, closed by respective covers 33 b and 34 b with seals 33 c and 34 c.The wells 33 and 34 of the side portion 4 are shown in FIG. 6 withoutthe respective covers. The ends 35 and 36 of the well 33 and of the well34, respectively, are shaped so as to be close to the peripheral wallsof the cylindrical seats of the cylinder-piston units and the respectivecovers 33 b and 34 b are shaped, for example, by drawing, so as toreproduce the shapes of the ends 35 and 36. A space 37 formed betweenthe covers 33 b and 34 b and the ends 35 and 36 of the respective wellsconstitutes part of the circuit for the cooling fluid.

The connectors 18 and 19 which, in the embodiment of FIGS. 5 and 6, areindicated 18 a and 19 a, are advantageously positioned in the vicinityof the centreline x—x of the caliper.

The main advantage of the caliper according to the present inventionlies in its reliability, as well as in maximum strength.

Naturally, in order to satisfy contingent and specific requirements, anexpert in the art may apply to the above-described caliper manymodifications and variations all of which, however, are included withinthe scope of protection of the invention as defined by the followingclaims.

What is claimed is:
 1. A caliper for a disk brake for motorcars, saidcaliper comprising a body having two side portions and two transversebridges connecting the two side portions, cylinder-piston units arrangedalong each side portion, and a circuit with an inlet and an outlet for afluid for cooling the cylinder-piston units, wherein the circuit for thefluid for cooling the cylinder-piston units comprises wells formed alongat least one of the side portions, the wells being of a depth such thatthey extend to a wall proximate to and delimiting at least one of thecylinder-piston units, the wells being closed by covers, at least one ofsaid covers bearing an appendage extending into a respective well inorder to occupy a predominant portion thereof, and the circuit alsocomprising connecting ducts for putting the wells into fluidcommunication with one another.
 2. The caliper according to claim 1,wherein each of the covers bears an appendage extending into respectivewells in order to occupy predominant portions thereof.
 3. The caliperaccording to claim 1, wherein the appendage of said at least one covercomprises a deformation of the cover.
 4. The caliper according to claim1, wherein the covers and the appendage are made of aluminum.
 5. Thecaliper according to claim 1, wherein the body is formed by mechanicalmachining from a solid semi-finished product made of aluminum alloy, andin that the wells and the ducts are produced by milling and by drilling,respectively.
 6. The caliper according to claim 1, wherein said circuitfor the fluid for cooling the cylinder-piston units comprises wellsformed along both of said side portions.
 7. The A caliper according toclaim 1, wherein portions of boundaries defining said wellsconcentrically follow a periphery of said cylinder-piston units.
 8. Thecaliper according to claim 1, wherein said at least one of said coversbearing said appendage is adapted such that said appendage follows thecontour of a boundary defining said respective well.
 9. The caliperaccording to claim 1, comprising four of said cylinder-piston units oneach side portion.
 10. The caliper according to claim 1, wherein atleast one of said wells extend into a space located substantiallybetween adjacent ones of said cylinder-piston units.
 11. The caliperaccording to claim 1, comprising three of said covers on each sideportion, and wherein a middle one of said three covers on each sideportion bears an appendage extending into a corresponding well in orderto occupy a predominant portion of said corresponding well.
 12. Acaliper for a disk brake suitable for automobiles, said calipercomprising a body having two side portions and two transverse bridgesconnecting the two side portions with cylinder-piston units arrangedalong each side portion, and a circuit with an inlet and an outlet wheresaid circuit is adapted to carry a fluid for cooling saidcylinder-piston units, wherein said circuit comprises wells formed alongat least one of said side portions, said wells being of a depth from asurface of said side portions such that said wells are at leastpartially defined by an inner wall, said inner wall being proximate toat least one of the cylinder-piston units and being substantiallyconcentric to said proximate cylinder-piston unit, said circuitcomprising ducts for putting said wells into fluid communication withone another, and wherein said wells are sealed closed with covers withat least one of the covers bearing an appendage extending into acorresponding well in order to occupy a portion thereof.
 13. The caliperaccording to claim 12, wherein said appendage is shaped to complementsaid inner wall.
 14. The caliper according to claim 12, wherein each ofthe covers bears an appendage extending into a corresponding well inorder to occupy a portion thereof.
 15. The caliper according to claim14, wherein said appendages are shaped to complement said inner wall.16. The caliper according to claim 12, wherein at least one of saidwells extend into a space located substantially between adjacent ones ofsaid cylinder-piston units.
 17. The caliper according to claim 16,wherein said at least one well extending into said space has two innerwalls, each wall corresponding to one of an adjacent pair ofcylinder-piston units such that said well is substantially cusp-shaped.18. A caliper for a disk brake for motorcars, said caliper comprising abody having two side portions and two transverse bridges connecting thetwo side portions, cylinder-piston units arranged along each sideportion, and a circuit with an inlet and an outlet for a fluid forcooling the cylinder-piston units, wherein the circuit for the fluid forcooling the cylinder-piston units comprises wells formed along at leastone of the side portions, the wells being of a depth such that theyextend substantially as far as the vicinity of one or more wallsdelimiting at least one seat of the cylinder-piston units, at least onewell having a space fitted between adjacent cylinder-piston units, andthe wells being closed by covers, at least one of the covers bearing anappendage extending into a corresponding well in order to occupy apredominant portion thereof, and wherein the circuit also comprisingconnecting ducts for putting the wells into fluid communication with oneanother.
 19. The caliper according to claim 18, wherein said at leastone well extending having said space is partially defined by two innerwalls, each wall corresponding to one of an adjacent pair ofcylinder-piston units such that said well is substantially cusp-shaped.20. The caliper according to claim 18, wherein said appendage is shapedto complement said one or more walls.